I guess this is more a feature request than a bug report (though IPv6 is gradually starting to be used).

Even though the distributed objects system is intended for use on a LAN, and IPv4 is pretty much exclusively used on LANs with IPv6 in practice only used for inter-lan comms, I'm still very much in favour of adding IPv6

But … IPv6 in gdomap makes no sense without adding IPv6 support to GNUstep distributed objects generally. That would imply a new version of the name server protocol and a new version of the distributed objects protocol (ie the definitions of the packet structures sent over the wire), so it's quite a big job.